Former child migrants from the UK have lodged claims against the New South Wales and Commonwealth governments and the charity that was responsible for their care.

Lawyers for the migrants, who were dispatched from England to Australia over a 40-year period, allege the children were subjected to physical, mental and sexual abuse during their time at the Fairbridge Farm in NSW.

Some of those former child migrants were at the Supreme Court in Sydney to lodge the case.

Former Fairbridge resident Bob Stephens says he lost his childhood after his arrival at the Molong farm in the NSW countryside at age seven.

Mr Stephens describes a range of horrifying behaviours he experienced or observed during his seven years at Molong.

"There were cottage mothers that belt the living daylights out of you with an electric cord [of a] jug, that was quite common," he said.

"You had to see the headmaster, who would cane you quite regularly with a hockey stick, quite brutally. This was a man who was well over six foot, was huge, was an ex-wrestler. So you can imagine the power that this man had behind him.

"You had other cottage mothers that would wake you up at 11:00pm because they found a cigarette butt on the floor and they'd have you standing on one leg till someone owned up to who had the cigarette butt, and this was at 11:00pm.

"This is absolute mental cruelty and affected a lot of children that way. The physical abuse that I was aware of, that I actually saw, I could name you names.

"In one instance a friend of mine, a girl who was a trainee, was sent to be one of the girls that worked in the office of an after-care officer, and he treated her like a slave, sexually and otherwise. And it's been well documented and this person got away with it."

The Fairbridge Foundation which ran Molong Farm was established by South African Rhodes scholar Kingsley Fairbridge.

Fairbridge was horrified at the conditions of British children living in institutions and his idea was to transport the children to lives of sunshine and plenty in Australia and other former British colonies.

Between 1938 and 1974, more than 800 children, some as young as four, were sent from England to the Fairbridge Farm School in Molong.

According to Mr Stephens, who arrived at Molong in 1952, the children were made to work the farm at the cost to their education.

"They were short of labourers to work on the farms so I was pulled out of school at the age of 12 to become a farm labourer on the farm itself, because it was a self-supporting farm. So I lacked education," he said.

Generations of damage

He says the damage to the children has lasted a lifetime and has in some instances been passed to the next generation.

"Because a lot of them with a lack of education have not had the right start in life, they've brought up their own families with great difficulty, because they were never given the chance to learn how to be parents and things of that nature, and today in their 50s, 60s and 70s are still suffering as a result of what happened to them at Fairbridge."

Law firm Slater and Gordon is representing the former Fairbridge children and Ken Fowlie is the lawyer handling the matter in court.

Mr Fowlie says the class action covers all residents at the Molong Fairbridge Farm School for any period between 1938 and 1974 and those who were physically or sexually assaulted and who have suffered a relevant injury including post traumatic stress disorder, anxiety or some other form of psychiatric or physical injury.

"Our claim is an attempt after years of trying to find a different solution to pursue those matters in court, to achieve justice for that group of former child migrants," he said.

"The nature of the damages that are being claimed are in the manner of a monetary compensation.

"It's not appropriate or possible for me at this point to speculate as to what they might be. That would ultimately be a matter for the court down the track if it determines that these cases that should be dealt with in that way.

"This is not a case where we're looking for a single sum, this is a case where everyone's situation has individual elements to it and ultimately if we're successful in this claim that will be a matter that the court will have to assess in due course."

Mr Stephens says financial compensation should go to the surviving former child residents but he says their children should also be compensated.

"It's the back-up these children need, it's educational opportunities to be given to their children," he said.

"So many of these former Fairbridge children had children and were unable to give them the educational opportunities because of the lack of their own education and the lack of their earning ability to be able to provide that education.

"So scholarships, things of that nature which I think are really important ... are things that should be provided for."